Arsène Wenger has said he will be forced to buy a new striker during the transfer window if Nicklas Bendtner is ruled out of action for more than a few weeks. The Dane damaged his ankle after scoring in Arsenal's victory over Cardiff City on New Year's Day and the club expect scan results within 24 hours to indicate the severity of his injury.

"If it's a question of up to three weeks, OK, but if it's a question of months the situation is quite [serious] … that's what we have to determine," Wenger said. When asked whether Bendtner being absent for more than three weeks would make Arsenal spend in January, he replied: "We would have to … You want to keep your chances for the season at the best possible level."

Bendtner has done well in recent weeks deputising for Olivier Giroud who was out with ankle trouble and will miss Saturday's FA Cup tie against Tottenham through illness.

The 20-year-old French striker Yaya Sanogo is scheduled to return to training after injury next week but Wenger does not want to place too much reliance during the run-in on a youngster with no Premier League experience, nor does he see Theo Walcott or Lukas Podolski as perfect centre-forward solutions.

Therefore, a long lay-off for Bendtner would compel him to spend. He claimed Arsenal have yet to consider any specific targets, despite being regularly linked with the Real Madrid forward Alvaro Morata, and denied that a move for Fulham's Dimitar Berbatov has been discussed.

The 32-year-old Bulgarian has the technique, finishing prowess and big-game experience that Arsenal would need and, unlike longer-term targets, is not involved in the Champions League or Premier League. A YouTube video appeared on his official Facebook page on Friday which had the title "Berbatov could fire Arsenal to the title".

Fulham are locked in a relegation struggle but Berbatov has reportedly been unhappy there and, although his performances have improved, at times this season he has looked ill-suited to a battle against the drop. He could be available at an affordable price.

"Ideally, you want a longer solution," Wenger said, "but a longer solution looks much more difficult to find in January than a stopgap. You can find a solution somewhere – a club that has financial trouble and wants to get rid of a big contract for five or six months but to find in January exactly the player who will be tomorrow's star in the longer term is much more difficult."